Steroids from a Far-Eastern Glass Sponge Aulosaccus sp.

Abstract

This report concerns the identification of steroid constituents of a Far-Eastern glass sponge Aulosaccus sp. (the Sea of Okhotsk), belonging to one of the least chemically investigated group of sponges. Steroid mixtures, isolated from the extract of Aulosaccus sp., were fractionated by high-performance liquid chromatography on normal-phase and/or reversed-phase columns, and the obtained fractions were analyzed by nuclear magnetic resonance spectroscopy and gas chromatographymass spectrometry. In result, 64 compounds, including 32 3-keto derivatives of sterols with saturated, Δ 7-, Δ 8(14)-, Δ 4-, and Δ 4,6-tetracyclic systems and 32 sterols (stanols, 4α-methyl-stanols, Δ 5-, Δ 7-, 4α-methyl-Δ 8(14)-sterols), were identified. Most of these steroids were not found in glass sponges earlier. The structures of 2 new steroids, 24-propyl-5α-cholest-24(28)Zen-3-one and 24-nor-cholest-4-en-3-one, were elucidated. Sterol esters were not found. 3-Keto derivatives of stanols were major components in the steroids of Aulosaccus sp. It is probable that association of Aulosaccus sp. with bacteria, capable of oxidizing sterols, led to the transformation of a significant part of sponge sterols into their 3-keto derivatives.

Structural Analysis of Oxidized Cerebrosides from the Extract of Deep-Sea Sponge Aulosaccus sp.: Occurrence of Amide-Linked Allylically Oxygenated Fatty Acids

“…In particular, some bacterial branched-chain, cyclopropane-containing FAs, and their monoenoic precursors were present in significant amounts in Aulosaccus sp. [ 32 ], and an overwhelming number of the sterols (stanols, Δ 5 -, Δ 7 -, and Δ 8(14) -sterols) of this sponge were oxidized to the corresponding 3-ketosteroids [ 37 ]. The occurrence of these FAs and steroids in Aulosaccus sp.…”